To Make Dressing
Combine all ingredients in a screw top jar and shake.
To Make Salad
Place noodles in a small heatproof bowl and cover with boiling water. Set aside for 5 mins to soften. Drain well.
Reserve 12 prawns for garnish. Roughly chop remaining prawns. Combine vermicelli, chopped prawns, snow pea sprouts, carrot, cucumber, radish, peanuts, shredded mint and coriander in a bowl.
Heat oil in a frying pan over medium high heat. Add rice paper sheets one at a time, cook until puffed and white. Drain on paper towel.
Add dressing to salad, toss gently to coat. Place rice paper sheets on a plate, fill with salad, top with reserved prawns, garnish with extra mint and coriander leaves.